<?php


$f=fopen('./tmp.txt','rb');
if($f==false){
    echo 'open file failed';

}else {
//    $res=fwrite($f,"adfgadfhetryqTGADSGADG");
    while(!feof($f)) {
        $str = fread($f, 4);
        echo $str;
    }
    echo file_put_contents('./s.txt','hello');
//    $str=file_get_contents("./s.txt",false,null,0,100);



}







fclose($f);


